Pulse Flow on the Colorado

For six million years, the Colorado River flowed from the Rocky Mountains to the Pacific Ocean. Now, after its waters are diverted to quench the thirst of millions of people, cattle, and thousands of acres of crops, the river is reduced to a trickle long before it reaches the Gulf of California.

Even as demand for water is increasing, the “use-it-or-lose-it” water laws in the West make it difficult for U.S. farmers to save their surplus water. South of the Mexican border, the Colorado River disappears completely. Over the years, as more of the river was dammed and diverted, the delta dried up. Farms, towns, and wetlands faded away.

For years, Jennifer Pitt of the Environmental Defense Fund dreamed of restoring water flow to the Colorado River Basin. This spring, she helped make it happen.

Along with a coalition of government agencies, conservation organizations, and hydrologists, Pitt worked to create a one-time release of more than 34 billion gallons of water to the Colorado River delta. After brokering conservation deals upstream, buying unused water rights from Mexican farmers downstream, and even helping renegotiate an international water treaty to temporarily allow for more flexible water trading, this “pulse flow” revived the Colorado and reconnected the river to the Pacific Ocean, if only for a few days.

Restoration ecologists on both sides of the border spent a year preparing for the release. Their goal was to simulate the historical seasonal floods of the Colorado River that nurtured wetlands and spawned fisheries, supporting communities and wildlife habitat across the floodplain. On March 23, 2014, the Morelos Dam on the U.S.-Mexican border opened to let the water flow. Over the next few weeks, it crept across 90 miles of dry, sandy riverbed to the Gulf of California. Along the way, it germinated cottonwood and willow trees and prompted celebrations as people gathered on the banks to splash in the water.

The river has run dry again, but Pitt and her colleagues at the Environmental Defense Fund continue to work to harness water markets that would allow the river to flow freely as it once did.